Microporous 3D graphitic carbons obtained by soft templating as carbocatalysts for aerobic oxidation

Abstract

[EN] Herein it is reported that chitosan, a natural filmogenic biopolymer, can undergo soft-templating in liquid phase under hydrothermal conditions by two typical structure directing agents, namely hexamethyleneimine (HMI) and tetraethylammonium (TEA) employed in the synthesis of zeolites MCM-22 and Beta, respectively. After templation, pyrolysis of chitosan under inert atmosphere renders 3D graphitic sponges with defined ultra- and microporous channels. These porous structured graphitic carbons exhibit much enhanced activity as metal-free catalyst in the aerobic oxidation of benzylamine compared to other analogous 2D graphene oxide and reduced graphene oxide, as well as large area active carbons. It is proposed that this superior activity of these 3D structured microporous carbons derives from confinement effects activating molecular oxygen and benzylamine within the micropores. Quenching studies indicate that the reactive oxygen species are mostly adsorbed within the pores of the 3D graphitic carbons